Rule-A-Matic Plus Float Switch

Product overview

The Rule-A-Matic Plus (model 40A, or 40FA with an in-line fuse holder) is an automatic bilge pump float switch for 12, 24 or 32 V DC pumps drawing up to 20 A at 12 V. It switches the pump on at 2 in (51 mm) of water and off at 3/4 in (19 mm); an integrated cover guards the float against debris and jamming.

Part of Pumps & Plumbing: Rule bilge pumps and float switches; Jabsco water pressure and washdown pumps and a manual marine toilet.

Key specifications

Model

Rule 40A

Brand

Rule

Models

40A; 40FA (with in-line fuse holder)

Voltage

12, 24 and 32 V DC

Maximum current

20 A at 12 V; 10 A at 24 V; 6.5 A at 32 V

Switches on

At 2 in (51 mm) of water

Switches off

At 3/4 in (19 mm)

Wire

14 AWG, 28 in (712 mm) long

Size

76 × 137 × 64 mm (3 × 5-3/8 × 2-1/2 in)

Guard

Integrated cover over the float

Figures as published by Rule (the maker’s page), checked 7 October 2026. Say the model and voltage you need with your quote.

Downloads

• MM Techno Plast catalogue 2026PDF, 7.9 MB, after a short formDownload